Epidemiological studies have linked the early-life socioeconomic environment and its affect on growth and maturation of children to many adult chronic diseases: heart disease, stroke, hypertension, diabetes mellitus, and chronic obstructive lung disease. This proposed study will collect secondary data to evaluate a possible early-life link to Alzheimer's disease (AD). AD is a neurodegenerative disorder characterized by neurofibrillary changes and amyloid deposits. The areas of the brain that show the earliest signs of AD (e.g., hippocampal formation, intracortical association areas, reticular formation) are the same areas of the brain that take longest to mature during childhood and adolescence. A poor childhood environment could prevent the brain from reaching complete adult levels of maturation. This inadequate level of maturation may put people at higher risk for AD. Objectives. We are proposing to investigate if the early-life factors such as father's occupation, number of siblings, mother's age, all which influence growth and maturation are associated with Alzheimer's Disease (AD). If deficient maturation is associated with a less developed brain then measures of early growth: low level of father's occupation, increase number of siblings, and maternal age should be associated with AD. We also plan to determine whether the potential association of these early-life factors and AD is modified by Apolipoprotein E Epsilon 4 genotype. Methods. The Genetic Differences study, a community based case-control study from the University of Washington, will form the subject base and provide verified cases and controls: approximately 371 cases and 345 controls. Early-life information will be collected through government records: birth certificates and census data. Apolipoprotien E genotype has been determined for the subjects. The causes of AD are not understood. This study could open the door to a new area of research on Alzheimer's Disease and aid in the understanding of gene-environment interactions.